When loading .mp3 files the duration is initially unknown. Before this
change it was reported as a large integer (since GST_CLOCK_TIME_NONE is
-1). Now it's correctly reported as 0.
Also rename gtk_media_stream_ended to
gtk_media_stream_set_ended, to avoid naming
collision with GtkMediaStream:ended.
The existing entry points still exist, deprecated
and marked as non-introspectable.
Update all internal uses.
Fixes: #4023
Some bindings can't handle the coexistence of
GtkMediaStream:prepared and gtk_media_stream_prepared.
Help them out by renaming the function to
gtk_media_stream_set_prepared, and rename
gtk_media_stream_unprepared as well, to match.
The existing entry points still exist, deprecated.
Update all internal uses.
Fixes: #4023
Visual Studio does not allow decorating functions with '__declspec (dllexport)'
if a prototype exists and is not decorated with '__declspec (dllexport)' as
well, so we cannot just decorate g_io_module_[load|unload|query] in the various
module sources with G_MODULE_EXPORT because the prototypes of these functions
have been marked with _GLIB_EXTERN, which equates to 'extern' unless overridden
Fix this by overriding _GLIB_EXTERN with the appropriate visibility flag, as we
have used to define _GDK_EXTERN. Unfortunately, we can't just use _GDK_EXTERN
G_MODULE_EXPORT as they may have not been defined yet for our use
Do this across the board for all modules, even if they are not buildable on
Visual Studio nor Windows, for consistency's sake.
